Heptazine, Cyclazine, and Related Compounds: Chemically-Accurate Estimates of the Inverted Singlet-Triplet Gap
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arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2023
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| _version_ | 1866913236818853888 |
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| author | Loos, Pierre-François Lipparini, Filippo Jacquemin, Denis |
| author_facet | Loos, Pierre-François Lipparini, Filippo Jacquemin, Denis |
| contents | Molecules that violate Hund's rule and exhibit an inverted gap between the lowest singlet $S_1$ and triplet $T_1$ excited states have attracted considerable attention due to their potential applications in optoelectronics. Amongst these molecules, the triangular-shaped heptazine, and its derivatives, have been in the limelight. However, conflicting reports have arisen regarding the relative energies of $S_1$ and $T_1$. Here, we employ highly accurate levels of theory, such as CC3, to not only resolve the debate concerning the sign but also quantify the magnitude of the $S_1$-$T_1$ gap. We also determine the 0-0 energies to evaluate the significance of the vertical approximation. In addition, we compute reference $S_1$-$T_1$ gaps for a series of 10 related molecules. This enables us to benchmark lower-order methods for future applications on larger systems within the same family of compounds. This contribution can serve as a reliable foundation for the design of triangular-shaped molecules with enhanced photophysical properties. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_19768 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Heptazine, Cyclazine, and Related Compounds: Chemically-Accurate Estimates of the Inverted Singlet-Triplet Gap Loos, Pierre-François Lipparini, Filippo Jacquemin, Denis Chemical Physics Materials Science Molecules that violate Hund's rule and exhibit an inverted gap between the lowest singlet $S_1$ and triplet $T_1$ excited states have attracted considerable attention due to their potential applications in optoelectronics. Amongst these molecules, the triangular-shaped heptazine, and its derivatives, have been in the limelight. However, conflicting reports have arisen regarding the relative energies of $S_1$ and $T_1$. Here, we employ highly accurate levels of theory, such as CC3, to not only resolve the debate concerning the sign but also quantify the magnitude of the $S_1$-$T_1$ gap. We also determine the 0-0 energies to evaluate the significance of the vertical approximation. In addition, we compute reference $S_1$-$T_1$ gaps for a series of 10 related molecules. This enables us to benchmark lower-order methods for future applications on larger systems within the same family of compounds. This contribution can serve as a reliable foundation for the design of triangular-shaped molecules with enhanced photophysical properties. |
| title | Heptazine, Cyclazine, and Related Compounds: Chemically-Accurate Estimates of the Inverted Singlet-Triplet Gap |
| topic | Chemical Physics Materials Science |
| url | https://arxiv.org/abs/2310.19768 |